تقويم الجريان غير المشبع لمبزل الحر تحت الظروف الحقمية لتربة مزيجة طينية غرينية :ألتنبأ عن األيصالبة المائية غير المشبعة ومقدات المحتوى المائي
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Abstract
Since no in situ studies exist for determining unsaturated hydraulic characteristics of Iraqi soils
during internal drainage under no evaporation conditions, a field study was conducted on a silty clay loam soil to determine unsaturated hydraulic conductivity using the Instantaneous Profile
Method(IPM) and to solve the one dimensional flow equation under gravity flow theory for obtaining easier method to predicting unsaturated hydraulic conductivity and water content profiles. An 8m 8m field plot was flooded for forty days and then covered to prevent evaporation from soil surface. Gravimetric samples were augured during 90 days of drainage following flooding as a function of depth. Soil water potentials was estimated from fitting a functional relation to laboratory measured water content and matric potential relations for the studied soil horizons. Unsaturated hydraulic conductivity was calculated according to Darcian flow theory. Unit gradient theory was used to obtain an analytical solutions for the general flow equation according to Lax-Sisson method by utilizing three explicit K(θ) functions. Unsaturated conductivity values for the studied layers ranged from 1.0964 to15.2389 cm.d-1 and from 0.00001 to 0.0004 cm.d-1 after 0.025d and 88.75 d of drainage respectively. A 1:1 relationship between measured and predicted conductivities reveled highly significant r-squared values of 0.918, 0.933, and 0.927 for the three functions respectively. Predicted conductivity values were higher by factors 1.378, 1.418, and 1.296 for the three equations respectively. Same amount of water was drained from studied depths during drainage cycle which resulted in parallel water content profiles. Except at the early drainage time, predicted water contents profile with Lax-Sisson's method matched satisfactorily measured water content profiles. Also 1:1 relationship of zero-intercept between measured and predicted water content values during drainage period produced high r-squared values of 0.960, 0.935, and 0.918 for the three functions respectively. Predicted water content values were higher by a factor 1.008, 1.011, and 1.043 than measured values for the three functions respectively. Results of this study showed that the Lax-Sisson's method was accurate in predicting unsaturated hydraulic conductivity and water content profiles under theory Of gravity drainage flow.
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* Albright, W.H., C. H. Benson, G.W. Gee, T. Abichoue, S.W. Tyler, and S.A. Rock. 2006.
Field Performance of Three Compacted Clay Landfill Covers. Vadose Zone J 5:1157-1171.
* Altman, S. J., B.W. Arnold, C. K. Ho, S. A. McKenna, R.W. Barnard, G.E. Barr, and R.R. Eaton. 1996. Flow calculations for Yucca Mountain groundwater travel time (GWTT-95). SAND96–0819. Sandia National Laboratories, Albuquerque, NM.
* Andraski, B.J. 1997. Soil-water movement under natural-site and waste-site conditions: A multiple-year field study in the Mojave Desert, Nevada. Water Resour. Res. 33:1901–1916.
* Basile, A, A. Coppola, R. De Mascellisa. 2006. Scaling Approach to Deduce Field Unsaturated Hydraulic Properties and Behavior from Laboratory Measurements on Small Cores. Vadose Zone J 5:1005-1016.
* Black, T. A.,. W. R. Gardner, and C. W. Thurtel. 1969. The prediction of evaporation, drainage, and soil water storage for a bare soil. Soil Sci. Soc. Amer. Proc. 33:655-660.
* Brooks, R. H. and A. T. Corey. 1964. Hydraulic properties of porous media. Hydrol. Pap. 3. 27pp. Colo. State Univ. Fort Collins.
* Byre, K.R., J.M. Norman, L.G. Bundy, and S.T. Gower. 1999. Equilibrium tension lysimeter for measuring drainage through soil. Soil Sci. Soc. Am. J. 63:536–543.
* Child, E. C., and N. Collis- George. 1950. The permeability of porous materials. Proc. Roy. Soc. (London), 201 A, 392-405.
* Davidson, J. M., L. R. Stone, D. R. Nielsen and M. E. Larue. 1969. Field measurement and use of soil-water properties,. Water Resour. Res. 5:1312-1321.
* Gee, G. W., J. M. Keller, and A. L. Ward . 2005. Measurement and Prediction of Deep Drainage from Bare Sediments at a Semiarid Site. Vadose Zone J. 4:32-40.
* Greacen, E. L., and L. R. Correl. 1981. Calibration. (In E. L. Greacen (ed.). 1981. Soil water measurement by the neutron method. pp.50-81. Csiro- Australia, 3002).
* Hanson, B., L. Schwanki, S. Gratten, and T. Prichards. 1997. Drip Irrigation for row crops. Division of Agricultural and Natural Resources, Publication 3376. University of California Irrigation Program, University of California, Davis.
* Hubbell, J. M., M. J. Nicholl, J. B. Sisson and D. L. McElroy. 2004. Application of a Darcian Approach to Estimate Liquid Flux in a Deep Vadose Zone. Vadose Zone J. 3:560-569.
* Jordan, C. 1968. A simple, tension-free lysimeter. Soil Sci. 105:81–86.
* Klute, A. 1972. The determination of hydraulic conductivity and diffusivity of unsaturated soils. Soil Sci. 113:264-276.
* Lax, P. D. 1972. The formation and decay of shock waves. Am. Math Monthly. 79:227-241.
* Libardi, P. L., K. Reichrdt, d. R. Nielsen, and J. W. Biggar. 1980. Simple field method for estimating soil hydraulic conductivity. Soil Sci. Soc Am. J. 44: 38-47.
* McElroy, D. L., and J. M. Hubbell and L. Randazzo. 2004. Evaluation of the Conceptual Flow Model for a Deep Vadose Zone System Using Advanced Tensiometer. Vadose Zone J. 3:170-182
* Nielsen, D. R., J. M. Davidson, J. W. Biggar, and R. J. Miller. 1964. Water movement through Panochy clay loam loam soil. Hilgardia 35:491-506.
* Phillips, F.M. 2001. Investigating flow and transport in the fractured vadose zone using environmental tracers. p. 271–294. In Conceptual models of flow and transport in the fractured vadose zone. National Academy Press, Washington, DC.
* Richards, L. A., W. L. Gardner, and G. Ogata. 1956. Physical processes determining water loss from soil. Soil Sci. Soc. Am. Proc. 20:310-314.
* Rose, C. W., and W.R. Stern. 1966. Determination of withdrawal of water from soil by crop roots as a function of depth and time. Aust. J. Soil Res. 5:11-19
* Rose, C. W., W. R. Stern, and J. E. Drumond. 1965. Determination of the hydraulic conductivity as a function of depth and water content for a soil in situ. Aus. J. Soil Res. 3:1-9.
* Salem, S. B. 1986. Data reduction methods for field estimated unsaturated hydraulic p[properties. M.Sc. Thesis. Kansas State University, Manhattan , Ks., USA.
* Salem, S. B. 2003. Unsaturated hydraulic characteristics of soil treated and untreated with fuel oil under surge and continuous irrigation. Ph.D Dissertation. College of Agriculture/ Baghdad University.
* Scanlon, B. R., R. C. Reedy, K. E. Keese, and Stephen F. Dwyer. 2005. Evaluation of Evapotranspirative Covers for Waste Containment in Arid and Semiarid Regions in the Southwestern USA. Vadose Zone J.4: 55-71
* Scanlon, B.R., S.W. Tyler, and P.J. Wierenga. 1997. Hydrologic issues in arid, unsaturated systems and implications for contaminant transport. Rev. Geophys. 35:461–490.
* Schawanki, L., B. Hanson, and T Prichard. 1998. Micro-irrigation of trees and vines. Division of agricultural and natural Resources. Publication 3378, University of California, Davis. Pp. 63-68.
* Si, B. C., and R. G. Kachanoski. 2003. Measurement of Local Soil Water Flux during Field Solute Transport Experiments, Soil Sci. Soc Am. J. 67:730-736
* Sisson, J. B., A. H. Ferguson, and M. Th. van Genuchten. 1980. Simple method for predicting drainage from field plot. Soil Sci. Soc. Am. J. 44:1147-1152.
* Stephens, D. B., and R. Knowlton. 1986. Soil water movement and recharge through sand at a semiarid site in New Mexico. Water Resour. Res. 22:881–889.
* Stone, L. R., T. C. Olson, and M. L. Horton. 1973. Unsaturated hydraulic conductivity for water management in situ. Proc. S. D. Acad. Sci. 52:168-178.
* Sun, A. Y. and D. Zhang. 2004. A Solute Flux Approach to Transport through Bounded, Unsaturated Heterogeneous Porous Media. Vadose Zone J. 3:513-526.
* Tuller, M. and D. Or. 2002. Unsaturated Hydraulic Conductivity of Structured Porous
Media: A Review of Liquid Configuration–Based Models. Vadose Zone J. 1:14-37
* Tuller, M., and D. Or. 2001. Hydraulic conductivity of variably saturated porous media—
Film and corner flow in angular pore space. Zone Journal 1:14-37.
* Van Bavel, C. H. M., G. B. Stirk, and K. J. Brust. 1968. Hydraulic properties of a silty clay loam soil and field measurement of water uptake by root. I. interpretation of water content and pressure profiles. Soil Sci. Soc. Am. Proc. 32:310-317.
* Van Genuchten, M. Th. 1980. A closed form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44:892-898
* Watson, K. K. 1966. An instantaneous profile method fro determining the hydraulic conductivity of unsaturated porous materials. Water Resour. Res. 2: 709-715.
* Watson, K. K. 1967. The measurement of the hydraulic conductivity of unsaturated porous materials utilizing zone of entrapped air. Soil Sci. Soc. Am Proc. 32:716-720.
* Wendroth, D., W., Ehler, J. W. Hopmans, H. kage, J. Halbertsma, and J. H. M. Wosten. 1993. Reevaluation of evaporation method for determining hydraulic function in unsaturated soils. Soil Sci. Soc. Am> J. 57:1436-1443.
* Zhu, J., B. P. Mohanty, A. W. Warrick, and M. Th. van Genuchten. 2004. Correspondenceand Upscaling of Hydraulic Functions for Steady-State Flow in Heterogeneous Soils. Vadose Zone J. 3:527-53